Rowallan Dam refurbishment work wins construction award
The refurbishment work recently completed on Hydro Tasmania’s Rowallan Dam won the utility a Tasmanian Project of the Year award from the Australian Institute of Project Management.
The award, given in the construction/engineering category, recognized excellence in project management for the refurbishment.
Rowallan Dam is a 43 m-high earth and rockfill dam on the Mersey River in northern Tasmania. The dam was built from 1964 to 1967 and comprises two embankments separated by a central concrete-lined spillway.
Rowallan Dam impounds water for a 10.5 MW hydroelectric generating station containing a single Francis turbine. The unit began operating in 1968.
In 2011, Rowallan Dam was assessed as part of a regular and planned risk assessment for all of the utility’s infrastructure. The dam’s performance was consistent with expectations for a dam of its design, construction and age. However, improved understanding of the dam’s risks meant Hydro Tasmania was able to reduce risks that were unforeseen in 1968. The primary outcome was that the risks were higher than previously thought, particularly in relation to the spillway’s tall and slender concrete walls.
The two-stage refurbishment involved strengthening the spillway walls and improving the capacity of the dam to withstand large floods. Work was conducted over the summers of 2013 to 2014 and 2014 to 2015.
The project cost A$13.4 million (US$9.9 million) and also included improving the core and filters within the embankment. The work was performed as part of Hydro Tasmania’s rolling 10-year asset management plan.
Bulgaria seeks design, preparation, supervision to build Yadenitsa Dam
Bulgaria utility Natsionalna Elektricheska Kompania EAD (NEK) seeks bids for design, document preparation and construction supervision of Yadenitsa Dam on Bulgaria’s Yadenitsa River.
Construction of Yadenitsa (or Jadenitsa) Dam would expand the lower reservoir of the 864 MW Chaira pumped-storage project, allowing it to generate for 22 continuous hours rather than the current 6.4 hours.
NEK last year recruited consultants for a program to rehabilitate: the Belmeken-Sestrimo-Chaira hydro complex featuring Chaira, the 375 MW Belmeken Pumped-Storage project, and the 240 MW Sestrimo and 120 MW Momina Klisura hydro projects; and the 14 MW Vacha 1 hydro project 110 kV switchyard and other hydro power project systems of integrated control. The Vacha 1 and 7 MW Vacha 2 plants are located at 80 MW Krichim Dam.
NEK now seeks bids for implementation of research and design works for updating the detailed design, and preparation of technical documents for award of construction works for the project to increase the volume of the lower reservoir of the Chaira project by construction of Yadenitsa Dam and a reversible pressure tunnel connection with Chaira Dam. Work also would include supervision during construction and preparation for project operation.
The work would require 86 months at an estimated cost of 3.5 million lev (US$2 million) in order to meet desired volume increases in the Chaira lower reservoir.
Lebanon seeks firms that can perform construction of Bisri Dam
The government of Lebanon invites applications for pre-qualification to construct Bisri Dam, a water supply dam in Lebanon.
The government’s Council for Development and Reconstruction recruited consultants in June, 2015, to serve on a Panel of Environmental and Social Experts to oversee construction of Bisri. The World Bank recruited consultants in February to perform a study of hydropower development in Lebanon.
The Council for Development and Reconstruction now invites applications for pre-qualification from contractors and firms for works and goods to construct Bisri Dam.
To be the second largest dam in Lebanon after Karoun Dam, Bisri is to be 73 meters tall and will store 125 million cubic meters of water for use in the greater Beirut region. Located upstream of the village of Bisri, the dam will collect water during the winter and spring for use during the summer and fall.
Niger seeks lender’s engineer to monitor 125 MW Kandadji Dam hydro project
The government of Niger invites expressions of interest to serve as lender’s engineer to monitor construction of the 125 MW Kandadji Dam hydroelectric project on the Niger River.
The government of Niger issued a similar solicitation last year and also recruited firms to serve as prime contractor. More recently, it called for expressions of interest to determine a management structure for the Kandadji hydro project.
The Kandadji Dam project includes construction of a dam for regulating the flow of the Niger River in order to provide water for irrigation, drinking, sanitation, ecology, grazing, fisheries, and about 629 GWh of electricity annually.
The government’s high commission on Niger Valley management, Haut Commissariat a l’Amenagement de la Vallee du Niger (HCAVN), now invites expressions of interest for a lender’s engineer to perform an operational audit of engineering, construction management, environmental and social aspects of the project. The work is to require about 1,780 man-days over 68 months.
Italy hydro developer seeks construction of Barghe hydro project
Italian hydropower developer Iniziative Bresciane S.p.A. plans to hire a company to provide civil and hydraulic works to construct the Barghe hydroelectric project at Barghe, Italy. The generating capacity of this facility was not disclosed.
Iniziative Bresciane seeks bids for civil, hydraulic and other works to construct the Barghe project. Works include an intake structure, fish ladder, penstock, underground ducts, surface power plant and a tailrace.
The work is expected to require 210 days at a cost of €4.9 million (US$5.4 million).
Kenya water agency seeks supervision for Thika Dam rehabilitation
Kenya’s Athi Water Services Board has invited expressions of interest to perform dam safety design and supervision for Thika Dam rehabilitation.
Athi Water Services recruited consultants in 2013 to serve as engineer’s representative in supervision of community water supply works that are part of the Thika Dam project on the Thika River. It also recruited firms for hydropower feasibility studies for the Chania River Outfall and Thika Dam off-take sites as well as design and supervision of a Chania River Outfall hydroelectric project. The government of Kenya recruited consultants in January to serve on a dam safety panel of experts to oversee construction of dam and reservoir projects in Kenya.
Athi Water Services now seeks expressions of interest from consultants for two phases of work over 29 months:
– Phase 1: Studies, design and preparation of bidding documents for dam safety inspection, instrumentation analysis, seepage and sedimentation studies, hydrological analysis, geotechnical investigation, topographic survey, embankment dam and slope stability analysis, emergency preparedness planning, and design of remedial works;
– Phase 2: Supervision of rehabilitation and remedial works.
Progress continues at 444 MW Vishnugad Pipalkoti project
According to the World Bank, construction continues on the 444 MW Vishnugad Pipalkoti hydroelectric project on the Alaknanda River, a major tributary of the Ganga River, in the district Chamoli in Uttarakhand, India.
THDC India Ltd., formerly Tehri Hydro Development Corp. Ltd., is the project developer and is scheduled to complete the US$922 million facility by December, 2017.
World Bank said in a statement: “The excavation of the upper strata of the diversion tunnel is complete and work on the lower strata is in progress. Works on the access tunnels to the water intake channel, the desilting chamber and the headrace tunnel are also underway.”
The approach road to the tunnel boring machine (TBM) platform is complete and preparatory work on the TBM platform is progressing with the TBM delivery and assembly scheduled to be completed in February 2016.
Vishnugad Pipalkoti is a run-of-river hydro scheme that includes the concrete gravity dam, an 8 mile-long headrace tunnel, an underground powerhouse that will contain four 111 MW vertical Francis turbine-generating units and the 2 mile-long tailrace tunnel.
Australian dam safety officials brace for dam failure in New South Wales
Residents near Jerrara Dam in rural Illawarra, New South Wales, Australia, on the NSW South Coast, were ordered to evacuate their homes in late August amidst fear the dam would fail as more than a foot of rain had fallen in the area by 3 p.m. on Aug. 25.
Jerrara Dam is an earth-fill, non-hydroelectric structure that impounds 430 acre-feet of water from Jerrara Creek. It was built in 1955 to supply water to the township of Kiama, which is 75 miles south of Sydney.
In 2013, the Kiama Municipal Council voted to decommission the dam for an estimated US$700,000 after safety concerns were raised about the dam’s structural safety. Contractors began decommissioning work in mid-July.
The NSW State Emergency Service issued the following statement in late August:
“Jerrara Dam (near Jamberoo, west of Kiama), which is in the process of being decommissioned, has shown signs of the wall failing due to heavy rainfall in the area. NSW SES advises residents living downstream of the dam need to take action to protect themselves and their properties and evacuate immediately.
“The Dam Failure Warning System for Jerrara Dam has issued a Red Alert, for areas downstream of the dam. This alert means dam failure is imminent. Failure of the dam will result in extremely dangerous flooding of the following areas: Mount Brandon Road, Jerrara Road and Jamberoo Road.”
Concerns centered around the fact that if the dam wall burst, water it impounds from Jerrara Creek would surge downstream into the Minnamurra River and flood parts of Minnamurra, including a nearby public school.
Evacuees were people in about six homes in the rural area.